Shaped charge perforation gun with phasing alignment and related equipment and methods

ABSTRACT

In a perforating gun, shaped charges can be configured to be rotatable with respect to each other and can be secured in a predetermined phasing by an alignment rod that can be helical with a pitch that defines the phasing. The shaped charges can be supported by holders, which can be directly connected to each other to be infinitely rotatable and can also be attached to and/or retained by the alignment rod via alignment connectors. The alignment connectors can also be configured to hold detonation and signal cords. This shaped charge alignment approach can facilitate manufacturing and assembly, for instance since a single design of holders and other components of the assembly can be used with various different alignment rods to provide the desired phasing based on well design criteria.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication 63/084,319, filed Sep. 28, 2020, the contents of which arehereby incorporated by this reference.

TECHNICAL FIELD

The technical field generally relates to perforating guns that utilizeshaped charges, and more particularly to assemblies for holding andorienting shaped charges in certain phasing alignments.

BACKGROUND

Shaped charges are commonly used in perforating guns in order to createperforations extending from a wellbore through the casing and into thesurrounding reservoir. Each shaped charge typically has certaincomponents, including a conical metallic liner, the main explosivecharge, the primer explosive, and the case that encloses the charge. Thedetonation of the charges is initiated via a denotator which isenergetically coupled via a detonating cord to each of the shapedcharges. Multiple shaped charges can be arranged in series within atubular carrier that is deployed within the casing of a well. The shapedcharges can also be arranged with a “phasing” where the explosivecharges are oriented to face outwardly at different directions along theseries of shaped charges. Typical phasing of shaped charges is at 60°,90°, 120°, or 180° where the angle is the radial angle between adjacentshaped charges. The shaped charges must be held in place at the desiredphasing, which has required dedicated tube assemblies typically cut bylaser, or other plastic retaining functional equivalents. There arevarious challenges with respect to the manufacture, assembly, deploymentand utilization of shaped charges, and there is a need for a technologythat addresses as least some of those challenges.

SUMMARY

According to an aspect, a perforating gun for deployment in a wellboreextending within an underground reservoir is provided. The perforatinggun includes a shaped charge holding assembly having shaped chargeholders that are arranged in a side-to-side configuration, whereadjacent pairs of the shaped charge holders are rotatable with respectto each other. The shaped charge holders are configured to receive andsupport respective shaped charges. The shaped charge holding assemblyalso has a mounting unit coupled to an end of the holding assembly; andan alignment system. The alignment system includes alignment connectorssecured to respective shaped charge holders or to respective shapedcharges, and an alignment rod having a mounting section configured to bemounted with respect to the mounting unit; and an alignment rod sectionextending from the mounting section along the holding assembly andconfigured to be connected to the alignment connectors. The alignmentrod section has a configuration to define connection points that areaxially spaced-apart from each other and positioned at radial locationsfor respectively coupling with the alignment connectors for orientationof the shaped charges at a predetermined phasing.

According to a possible implementation, the alignment rod section has ahelical configuration.

According to a possible implementation, the helical configuration of thealignment rod section has a circular helical form.

According to a possible implementation, the helical configuration of thealignment rod section has a square helical form.

According to a possible implementation, the helical configuration of thealignment rod section has a regular helical form over a length thereof.

According to a possible implementation, the alignment rod section isarranged to wind helically around the holding assembly.

According to a possible implementation, adjacent alignment connectorsdefine an axial holder spacing (S) therebetween, and the helicalconfiguration of the adjustment rod section has a pitch (P) that ispredetermined to position the connection points of the adjustment rodsection at the radial locations for coupling with the alignmentconnectors.

According to a possible implementation, the axial holder spacing (S) issmaller than the pitch (P).

According to a possible implementation, the pitch (P) is an integermultiple of the axial holder spacing (S).

According to a possible implementation, the pitch (P) is equivalent toapproximately 2S to provide a 180° phasing between adjacent shapedcharge holders.

According to a possible implementation, the pitch (P) is equivalent toapproximately 3S to provide a 120° phasing between adjacent shapedcharge holders.

According to a possible implementation, the pitch (P) is equivalent toapproximately 4S to provide a 90° phasing between adjacent shaped chargeholders.

According to a possible implementation, the pitch (P) is equivalent toapproximately 6S to provide a 60° phasing between adjacent shaped chargeholders.

According to a possible implementation, the alignment rod section andthe mounting section are formed as a one-piece solid rod.

According to a possible implementation, the alignment rod is composed ofmetal.

According to a possible implementation, the mounting unit comprises aslot and the mounting section of the alignment rod is shaped to beinsertable within the slot.

According to a possible implementation, the slot has a circularcross-section and the mounting section has a cylindrical shape.

According to a possible implementation, the mounting section isstraight.

According to a possible implementation, the mounting unit is a topmounting unit.

According to a possible implementation, the mounting unit is rotatablycoupled to a top-most shaped charge holder.

According to a possible implementation, the perforating gun furthercomprises a carrier in which the mounting unit, the holding assembly andthe alignment system are located.

According to a possible implementation, the mounting unit comprises anindexing tab extending radially therefrom and configured to fit within acorresponding groove of the carrier to prevent rotation between thecarrier and the mounting unit.

According to a possible implementation, the carrier has a scallopedshape with narrower sections being aligned with respective shapedcharges.

According to a possible implementation, the shaped charge holders areinfinitely rotatable with respect to each other.

According to a possible implementation, the shaped charge holders arerotatably mounted directly to each other.

According to a possible implementation, the shaped charge holders eachinclude an annular body comprising a first open end for receiving ashaped charge therein, and a second opening through which an end of theshaped charge can pass for connection with a detonation cord; a firstcoupling component extending from a first side of the annular body; anda second coupling component extending from a second side of the annularbody, where the first coupling component and the second couplingcomponent of adjacent shaped charge holders are rotatably connectabletogether to enable rotation of the adjacent shaped charge holders withrespect to each other.

According to a possible implementation, the first coupling component isprovided on a downhole side and the second coupling component isprovided on an uphole side for each of the shaped charge holders.

According to a possible implementation, the first coupling component isa male component and the second coupling component is a femalecomponent.

According to a possible implementation, the male component comprises amushroom-shaped member comprising a post extending from the annular bodyand a head.

According to a possible implementation, the post is cylindrical, and thehead is inwardly tapered extending away from the post.

According to a possible implementation, the head has a frusto-conicalshape.

According to a possible implementation, the female component includesside walls extending from the annular body and defining a chamber forreceiving the head of the male component; and a lip extending inwardlyfrom an extremity of the side walls.

According to a possible implementation, the lip and the head areconfigured such that, upon coupling of the male and female components,the lip fits over and retains the head within the chamber to inhibitaxial displacement while allowing rotation between adjacent shapedcharge holders.

According to a possible implementation, the first and second couplingcomponents are configured to axially retain the holders together toresist or prevent decoupling.

According to a possible implementation, the male component has flexiblemembers and the female component has a rigid wall.

According to a possible implementation, a top-most shaped charge holderis directly rotatably connected with respect to the mounting unit.

According to a possible implementation, each of the alignment connectorsincludes a main section for coupling the shaped charge with a detonationcord; and an alignment section configured to be secured to the alignmentrod.

According to a possible implementation, the alignment section comprisesan arm extending from the main section and comprising a clip securableabout the alignment rod.

According to a possible implementation, the alignment connectorcomprises a second arm extending from the main section and comprising asecond clip securable to a signal cord.

According to a possible implementation, the alignment connector isformed from a single sheet metal piece.

According to a possible implementation, the main section comprises abase plate, opposed side walls extending from the base plate, and anupper plate defining a detonator cord passageway, and wherein the upperplate has an opening defined therein for receiving an end of the shapedcharge into the passageway for connection to the detonator cord.

According to a possible implementation, the arm comprises an obliquesection extending at an angle toward the shaped charge, the clip beinglocated at an extremity of the oblique section.

According to a possible implementation, the angle is between 30 and 60degrees.

According to a possible implementation, the clip comprises a clampcomprising two opposed resilient members that define an insertion regiontherebetween and extend outwardly from the oblique section away from theshaped charge.

According to a possible implementation, the clamp is configured toreceive and compress the alignment rod within the insertion region.

According to a possible implementation, the alignment connector isformed as an integral connected part of the alignment rod, or is formedas a separate piece.

According to a possible implementation, the alignment rod has a circularcross-section.

According to a possible implementation, the perforating gun furtherincludes a bottom mounting unit that is rotatably coupled to abottom-most shaped charge holder, and comprises a cavity to receive afree bottom end of the alignment rod.

According to a possible implementation, each of the shaped chargeholders comprises resilient projections configured to retain thecorresponding shaped charge in the holder.

According to a possible implementation, each of the shaped chargeholders comprise a resilient mounting ring configured to retain thecorresponding shaped charge in the holder.

According to a possible implementation, each of the shaped chargeholders include a mounting ring comprising a slit and configured toreceive the shaped charge; and a resilient retention wire insertable inthe slit to engage and retain the corresponding shaped charge in theholder.

According to a possible implementation, the alignment connectors formedas part of respective holders.

According to a possible implementation, the alignment connectors areconfigured to couple the alignment rod section to the shaped charges.

According to another aspect, a kit for holding shaped charges atdifferent phasings is provided. The kit includes a series of shapedcharge holders that are rotatably connectable and configured to holdshaped charges; alignment connectors securable with respect torespective shaped charge holders and/or shaped charges; a mounting unitcouplable to an end one of the shaped charge holders; and a set ofalignment rods having different alignment rod configurations, each ofthe alignment rods being mountable to the mounting unit and to each ofthe alignment connectors and having a configuration for orientation ofthe shaped charge holders in a predetermined phasing.

According to another aspect, a use of a helical member for alignment ofa series of shaped charges in a predetermined phasing in a perforationgun deployable within a wellbore is provided.

According to another aspect, a perforating gun for deployment in awellbore extending within an underground reservoir is provided. Theperforating gun includes a shaped charge holding assembly having shapedcharge holders that are arranged in a side-to-side configuration andwherein at least some adjacent pairs of the shaped charge holders areinfinitely rotatable with respect to each other in a rotation state; amounting unit coupled to the holding assembly; and an alignment system.The alignment system includes alignment connectors securable withrespect to respective shaped charge holders or shaped charges; analignment member comprising a mounting section configured to be mountedwith respect to the mounting unit to secure the alignment member withrespect thereto; and an elongated alignment section extending from themounting section along the holding assembly and configured to secure theshaped charges via the alignment connectors to orient the shaped chargesin a predetermined phasing in an aligned state.

According to a possible implementation, the alignment member comprisesan alignment rod.

According to a possible implementation, the alignment member comprisesan alignment tube.

According to a possible implementation, the perforating gun furtherincludes a cord or wire extending within a hollow core of the alignmenttube to provide electrical communication or grounding.

According to a possible implementation, the alignment member comprisesan alignment plate.

According to a possible implementation, the alignment member is composedof metal and provides electrical conduction.

According to a possible implementation, the alignment member comprisesan electrically insulating sleeve around an outer surface thereof.

According to a possible implementation, the shaped charge holders aredirectly coupled to each other.

According to a possible implementation, the shaped charge holders areindependently rotatable with respect to each other.

According to a possible implementation, the mounting unit comprise aslot shaped and sized to receive the mounting section of the alignmentmember.

According to a possible implementation, the slot and mounting sectionare configured so the mounting section has free axial movement withinthe slot.

According to a possible implementation, the alignment member has asingle elongated alignment section.

According to a possible implementation, the alignment system has asingle alignment member for phasing the shaped charges.

According to another aspect, a perforating gun for deployment in awellbore extending within an underground reservoir is provided. Theperforating gun includes a shaped charge holding assembly having shapedcharge holders that are arranged in a side-to-side configuration alongthe perforating gun; a mounting unit coupled to an end of the holdingassembly; and an alignment system. The alignment system has alignmentconnectors securable with respect to respective shaped charge holdersand/or shaped charges; and an alignment rod comprising a mountingsection configured to be mounted with respect to the mounting unit tosecure the alignment rod with respect thereto; and a helical alignmentsection extending from the mounting section along the holding assemblyand configured to secure each of the shaped charge holder and/or shapedcharges via the alignment connectors, the helical alignment sectionhaving a predetermined helical configuration with a pitch for providinga predetermined phasing of the shaped charges.

According to a possible implementation, at least some of the shapedcharge holders are rotatable with respect to each other prior to beingheld in place by the alignment system.

According to a possible implementation, the shaped charge holders areinfinitely rotatable with respect to each other prior to being held inplace by the alignment system.

According to another aspect, a shaped charge holder is provided. Theshaped charge holder includes an annular body comprising a first openend for receiving a shaped charge therein, and a second opening throughwhich an end of the shaped charge can pass for connection with adetonation cord; a first coupling component extending from a first sideof the annular body; and a second coupling component extending from asecond side of the annular body; and wherein the first couplingcomponent and the second coupling component are configured such thatadjacent shaped charge holders are rotatably connectable together byengagement of the first and second coupling components to provideinfinite rotation with respect to each other about a longitudinal axis.

According to a possible implementation, the first and second couplingcomponents are configured axially retain adjacent holders together toresist or prevent decoupling.

According to a possible implementation, the first and second couplingcomponents provide a male-female connection.

According to a possible implementation, the male component is rigid, andthe female component comprises resilient arms to receive and snap ontothe male component.

According to a possible implementation, the female component comprises acavity defined by rigid walls and the male component comprise resilientarms insert and snap into the female component.

According to another aspect, a multifunctional connector for use in aperforating gun is provided. The multifunctional connector includes adetonation cord clip for securing a detonation cord against a shapedcharge; a signal cord clip for securing a signal cord extending alongthe perforating gun; and an alignment member clip for securing analignment member that is configured to secure shaped charge holders in aphasing arrangement.

According to another aspect, a multifunctional connector for use in aperforating gun is provided. The multifunctional connector includes adetonation cord clip for securing a detonation cord against a shapedcharge; an arm extending away from the detonation cord clip andcomprising a clamp at an extremity thereof, the clamp being configuredfor securing to an alignment rod used to orient shaped charge holders ina phasing arrangement.

According to another aspect, a downhole tool for deployment in awellbore extending within an underground reservoir is provided. Thedownhole tool includes a series of components that are arranged in aside-to-side configuration along the tool and wherein at least someadjacent pairs of the components are rotatable with respect to eachother; a mounting unit coupled to an end of the series of components;and an alignment system comprising alignment connectors securable withrespect to respective components; an elongated alignment membercomprising a mounting section configured to be mounted with respect tothe mounting unit to secure the alignment rod with respect thereto; anda helical alignment section extending from the mounting section alongthe series of components and configured to secure each of the componentsvia the alignment connectors, the helical alignment section having apredetermined helical configuration with a pitch for providing apredetermined phasing of the components.

According to a possible implementation, the components comprise shapedcharge holders or shaped charges.

According to another aspect, a process for perforating an undergroundreservoir is provided. The process includes deploying a perforating gundown a wellbore in an underground reservoir, the perforating gun beingdefined as described in any of the claims or otherwise herein;detonating the shaped charges to perforate the reservoir; and retrievingthe perforating gun from the wellbore.

According to a possible implementation, the underground reservoir issuitable for geothermal activities.

According to a possible implementation, the underground reservoircomprises hydrocarbons for recovery.

According to another aspect, a method for manufacturing a perforatinggun is provided. The method includes mounting a series of shaped chargeholders together so as to be rotatable with respect to each other;mounting shaped charges within the holders; connecting a first endholder to a first mounting unit; aligning the shaped charges in apredetermined phasing, comprising providing an alignment systemcomprising an alignment member and alignment connectors, the alignmentmember having a predetermined configuration for the predeterminedphasing; mounting the alignment member to the first mounting unit sothat the alignment member extends along the series of shaped chargeholders; rotating the holders to respective positions for beingconnectable with respect to the alignment member; and securing theshaped charges and/or the holders to the alignment member via thealignment connectors; mounting a second mounting unit to a second endholder opposite the first end holder, thereby forming a phased shapedcharge system; and installing a carrier about the phased shaped chargesystem.

According to another aspect, a perforating gun for deployment in awellbore extending within an underground reservoir is provided. Theperforating gun includes shaped charge holders that are arranged in aside-to-side configuration and wherein adjacent pairs of the shapedcharge holders are rotatable with respect to each other, the shapedcharge holders being configured to receive and support respective shapedcharges; an alignment system comprising an alignment rod extending alongthe shaped charge holders and being connectable to the holders or theshaped charges at respective predetermined connection points, thealignment rod having a configuration to orientate the shaped charges ina predetermined phasing upon coupling at the predetermined connectionpoints.

According to another aspect, a perforating gun for deployment in awellbore extending within an underground reservoir is provided. Theperforating gun includes shaped charge holders that are arranged in aside-to-side configuration and wherein at least some adjacent pairs ofthe shaped charge holders are infinitely rotatable with respect to eachother in a rotation state; an elongated alignment member extending alongthe shaped charge holders and configured to secure the shaped charges toorient the shaped charges in a predetermined phasing in an alignedstate.

According to another aspect, a perforating gun for deployment in awellbore extending within an underground reservoir is provided. Theperforating gun includes shaped charge holders that are arranged in aside-to-side configuration; an alignment system comprising alignmentconnectors securable with respect to respective shaped charge holdersand/or shaped charges; and an alignment rod comprising a helicalalignment section extending along the shaped charge holders andconfigured to secure each of the shaped charge holders and/or shapedcharges via the alignment connectors, the helical alignment sectionhaving a predetermined helical configuration with a pitch for providinga predetermined phasing of the shaped charges.

According to another aspect, a downhole tool for deployment in awellbore extending within an underground reservoir is provided. Thedownhole tool includes a series of components that are arranged in aside-to-side configuration along the tool and wherein at least someadjacent pairs of the components are rotatable with respect to eachother; an alignment system comprising a helical alignment sectionextending from the mounting section along the series of components andconfigured to secure each of the components via the alignmentconnectors, the helical alignment section having a predetermined helicalconfiguration with a pitch for providing a predetermined phasing of thecomponents.

According to another aspect, a method for manufacturing a perforatinggun is provided. The method includes mounting a series of shaped chargeholders together so as to be rotatable with respect to each other;mounting shaped charges within the holders; aligning the shaped chargesin a predetermined phasing, comprising providing an alignment systemcomprising an elongated alignment member having a predeterminedconfiguration for the predetermined phasing; mounting the elongatedalignment member about the shaped charge holders; rotating the holdersto respective positions for being connectable with respect to theelongated alignment member; and securing the shaped charges and/or theholders to the elongated alignment member to produce a phased shapedcharge assembly; and installing the phased shaped charge assembly in acarrier.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partial transparent side perspective view of an exampletandem sub coupled to a perforating gun with a holding assembly thatincludes rotatably mounted shaped charge holders, and an alignmentsystem that includes an alignment rod secured with respect to the shapedcharges within a tubular carrier.

FIG. 2 is a side perspective view of an example perforating gun internalsubassembly that can include top and bottom mounting units and shapedcharge holders.

FIG. 3 is a side cut view of part of an example perforating gunsubassembly within a carrier.

FIG. 4 is a side perspective view of part of an example shaped chargeholding assembly.

FIG. 5 is a perspective view of an example shaped charge holder.

FIG. 6 is a side view of an example perforating gun subassembly thatincludes holders for shaped charges as well as an alignment connector,which in this example also functions as a detonator cord clip or “detcord clip”.

FIG. 7 is a perspective view of an example alignment connector.

FIG. 8 is a perspective view of an example top mounting unit.

FIG. 9 is a perspective view of an example bottom mounting unit.

FIG. 10 is a partially exploded, partially transparent, partially cutside view of an example tandem sub.

FIG. 11 is an example alignment rod.

FIG. 12 is a perspective view of a perforating gun subassembly withshaped charges.

FIG. 13 is a perspective view of part of a perforating gun subassemblyand a tandem sub.

FIGS. 14 to 18 are views of an example top mounting unit.

FIGS. 19 to 21 are views of an example bottom mounting unit.

FIG. 22 is a side cut view of part of the perforating gun subassemblyand part of the tandem sub.

FIG. 23 is a perspective view of part of an example holding assemblywith alignment connectors integrated as part of the holders.

FIGS. 24 to 30 are views showing different example holders.

FIG. 31 is a perspective view of part of a PCB assembly coupled to a topmounting unit of a perforating gun.

FIGS. 32A to 32G are schematics of perforating gun subassemblies showingdifferent phasing and alignment scenarios.

FIG. 33 is a schematic of a plate shaped alignment member withintegrated clips.

FIGS. 34A and 34B are schematics of example rotatable connectionsbetween adjacent holders.

FIG. 35 is a cross-sectional view of another implementation of theperforating gun, showing a PCB assembly having a cartridge, according toan implementation.

FIG. 36 is a perspective exploded view of the perforating gun shown inFIG. 35 .

FIG. 37 is an enlarged view of a portion of the perforating gun shown inFIG. 36 , showing a cartridge insertable in a tandem sub, according toan implementation.

FIGS. 38 and 39 are cross-sectional views of the cartridge and tandemsub shown in FIG. 37 , showing a pressure bulkhead engageable betweenthe tandem sub and the cartridge, according to an implementation.

FIG. 40 is a cross-sectional perspective view of a portion of thecartridge and tandem sub assembly shown in FIG. 39 , showing thepressure bulkhead engaging a connection bore of the cartridge, accordingto an implementation.

FIG. 41 is an exploded perspective view of the cartridge and a mountingunit of the perforating gun, showing a grounding system of thecartridge, according to an implementation.

FIG. 42 is a perspective view of the cartridge, showing a detonatorextending therefrom, according to an implementation.

FIG. 43 is a side view of the cartridge shown in FIG. 42 .

FIG. 44 is a cross-sectional perspective view of a portion of thecartridge, showing the detonator supported by a support member withinthe cartridge, according to an implementation.

FIG. 45 is a cross-section view of a portion of the perforating gunshown in FIG. 35 , showing the detonator positioned proximate adetonation chord, according to an implementation.

DETAILED DESCRIPTION

Techniques described herein relate to methods and systems for holdingshaped charges in a wellbore in the context of perforating operations.In some implementations, the shaped charges can be held in place with adesired phasing using shaped charge holders that are rotatable about theaxis of the perforating gun and can connect to an alignment rod atpredetermined locations due to the spacing between the holders and theconfiguration of the alignment rod. For example, the alignment rod canhave a helical section having a certain pitch while the holders arespaced-apart axially to define a spacing such that connectors associatedwith respective holders intersect with the path of the helical alignmentrod at certain radial locations, thus orienting the charges to have adesired phasing. In one example, the helical alignment rod can have apitch that is six times the spacing between the connectors of theholders, thus enabling six holders to be connected per pitch length andthereby providing a shaped charge phasing of 60°. In a similar manner,the charge spacing and alignment rod pitch can be modified to providethe phasing desired for a given perforation operation, including amultitude of pitches. In addition, for a given holding assembly having aset spacing between holders, alignment rods of different pitches can bemanufactured and used with the holding assembly in order to provide thedesired phasing for the charges.

Referring to FIG. 1 , an example implementation of a perforating gun 2is illustrated. The perforating gun 2 can include a shaped chargeholding system 6 and a tandem sub 4. The holding system 6 can also bereferred to a perforating gun subassembly. The perforating gunsubassembly 6 can include a shaped charge holding assembly 8, opposingmounting units (including a top mounting unit 12 and, as shown in FIG. 2, a bottom mounting unit 14), and an alignment system. The peroratinggun subassembly 6 is housed within a carrier 10 which has a tubularform. The holding assembly 8 can include one or more shaped chargeholders 16 arranged in series, and which can be independently andinfinitely rotatable with respect to each other. The holding assembly 8can be made up of the holders 16 which are directly coupled together, orcan include holders that are interconnected via other components thatenable certain functions such as rotation between the holders,reinforcement, and so on.

The holding assembly 8 cooperates with an alignment system which caninclude multiple alignment connectors 18 that are operativelyconnectable with respect to respective charges 22, and an alignmentmember 20 (e.g., alignment rod) that is securable to the top mountingunit 12 and to each of the alignment connectors 18 along its length. Thealignment connectors 18 can take the form of retaining clips that attachto the shaped charges, as illustrated here, or as connectors that arepart of or attached to the holders 16. The alignment rod 20 has aconfiguration, such as a helical configuration, that extends around andalong the series of holders 16 such that the alignment rod definesconnection points that are axially spaced-apart from each other andpositioned at radial locations for respectively coupling with thealignment connectors 18 for orientation of the shaped charges 22 at apredetermined phasing. For example, the helical part of the alignmentrod can have a pitch (P) that is coordinated with the spacing (S)between the connectors 18 such that the rod intersects with the axialpositions of the connectors 18 at predetermined radial locations toprovide a desired phasing of the shape charges 22. Depending on thepitch of the helical segment of the alignment rod and the spacingbetween the connectors 18, various phasing configurations can beachieved. FIG. 1 illustrates a phasing of 60°, for example.

In one implementation, a given holding assembly 8 can be designed toprovide a set spacing between the connectors 18, and multiple alignmentrods 20 can be manufactured having different configurations (e.g.,different pitches with the same diameter if helical) while beingcompatible with the set spacing of the holding assembly 8. Thus, thesame holding assembly 8 design can be used with any number of alignmentrods 20 to enable the phasing of interest for the shaped charges. InFIG. 1 , for example, shaped charges 22 are illustrated mounted withingrespective holders 16.

FIG. 2 illustrates the perforating gun subassembly 6 that includes thetop and bottom mounting units 12, 14, the shaped charge holding assembly8, and the alignment system including the alignment connectors 18 andthe alignment member 20. The subassembly 6 can be configured to behoused in the carrier and to be coupled to the tandem subs on eitherend.

Referring to FIG. 3 , the top mounting unit 12 can optionally have analignment tab 23 a that fits into a corresponding groove 23 b or keywayin the carrier 10 to prevent rotation of the top mounting unit 12 withinthe carrier 10. The alignment member 20 is insertable into the topmounting unit which is connected to the top-most shaped charge 22. Thealignment tab 23 a of the top mounting unit fits into the groove of thecarrier, which facilitates the indexing of the shaped charges based onthe curvature or configuration of the alignment rod. The alignment tab23 a can therefore provide a fixed point so that the orientation of eachcharge is indexed relative to the keyway in the carrier. This can beuseful for certain configurations, such as 0 or 180 degree phasings,where it is desirable for all of the charges along the entireperforating gun, including multiple holding assemblies, to be in thesame phase. Alternatively, the assembly may not be indexed in this wayso that the charges of a given assembly are in phase with each other butnot necessarily with other gun assemblies above or below. The alignmenttab can also serve the purpose of setting the internal assembly at a setdepth in the carrier. It is noted that the tab and groove are notnecessary, and the components can be allowed to rotate within thecarrier or can be secured to the carrier in another fashion.

The top mounting unit 12 can be a single configuration plastic moldedcomponent that also provides an electrical path between guns. The topmounting unit 12 can be configured to align the first charge holder anddet cord within the gun carrier for competent electrical connections andphasing. The bottom mounting unit 14 can also be a single configurationplastic molded component. The bottom mounting unit 14 can be configuredto centralize last charge holder within gun carrier. Other centralizingmechanisms could also be used.

In addition, in some implementations, the alignment system could becoupled to the holding assembly 8 without being connected to the top orbottom mounting unit 12,14. In this scenario, the holding assembly 8would have the desired alignment and phasing of the shaped charges, asdesired based on the alignment member that is used, but the holdingassembly 8 could rotate freely with respect to the top and bottom units12,14 if the end holders are rotatably coupled to those units. Thus, theshaped charges would retain their phasing, although they may not be“indexed” or fixed with respect to the top or bottom units. In anotherpossible implementation, the top end-most holders 16 could be fixedlyconnected to the top unit 12 so that the holder does not rotate withrespect to the top unit 12, which the rest of the holders 16 arerotatably coupled to each other, and the alignment member could beattached only to the holders 16 to provide the phasing. In thisimplementation, the holders could be indexed or fixed relative to thetop unit due to the connection of the top end-most holder 16 to the topunit 12. A similar setup could be used where the bottom end-most holder16 is fixedly connected to the bottom unit 14. It is also possible todesign the system such that one or more of the end-most holders isintegral with the respective top or bottom unit. Thus, in light of theabove, it is understood that the alignment bar may or may not be mountedto the top or bottom units, the end-most holders can be coupled to orpart of the top or bottom units in various ways, and the holdingassembly may or may not be free to rotate when in the aligned phasedconfiguration depending on how it is coupled to adjacent components.

Furthermore, the top unit 12 can be provided to enable several functionsof interest, e.g., providing a rotatable electrical path for signalcommunication, providing alignment for the detonator and detonatingcord, aligning the shaped charges to their respective carrierscallops/grooves by indexing its assembled location to its respectivecarrier feature, and retaining and providing an indexable location/anglefor the alignment rod. The top and bottom units can also providecentralizing functions within the carrier, as well as modularity formanufacturing perforating guns. However, it is noted that the system maybe designed without a top unit and/or a bottom unit, such that theholding assembly is connected more directly to the adjacent componentsof the perforating gun. The perforating gun design could be adapted ifthe top and/or bottom units were removed, while keeping the alignmentsystem for the shaped charges retained in the holders.

Referring to FIG. 2 , the holding assembly 8 is constructed such thatthe series of holders 16 are sandwiched in between opposing mountingunits 12, 14 and the alignment rod 20 is also inserted in place withinat least one of the mounting units, e.g., the top mounting unit 12 asillustrated. The holders 16 can be mounted with respect to each other invarious ways. For example, in the illustrated implementation, theholders are 16 are mounted directly to each other so as to be rotatablewith respect to each other. Alternatively, the holders 16 could beinterconnected via an intermediate mechanism that enables relativerotation between the holders 16. The holders 16 could also be mountedabout a central rod about which the holders could rotate. The holdingassembly 8 could also include other components that provide structuraland functional features of interest. The alignment rod 20 can be fixedlysecured to the top mounting unit 12, or it can simply be inserted into aslot and is prevented from coming out once it is mounted to thealignment connectors and the bottom mounting unit is attached to thebottom-most holder, thus enclosing the alignment rod axially with littleto no play. It is also noted that the mounting unit to which the holdersand alignment member are connected can take many forms and can alsoinclude multiple sub-components that are coupled together.

Referring to FIGS. 19 and 20 , the lower end of the alignment rod can belocated within the annular cavity of the bottom mounting unit as a freeend. The alignment rod has sufficient rigidity and strength such thatwhen it is connected along the assembly is does not need securing at thebottom end, but simply floats in the cavity of the bottom mounting unit.Alternatively, the rod could be secured to or within the bottom unit. Inaddition, the bottom unit 14 can have an outer annular cavity for thealignment member, as well as an inner annular cavity that can beprovided to receive excess wire, if needed.

The structure that enables rotation of the holders relative to eachother can take various forms and can also enable different types ofrotation. In some implementations, the holders 16 are infinitely andindependently rotatable with respect to each other about a longitudinalaxis extending along the holding assembly 8. This means that each holder16 can be rotated about the axis freely and independently without anystructure causing rotation to stop. In an alternative implementation,the holders could be rotatable with respect to each other, but with somelimitations in the rotation, e.g., only 360° rotation permitted back andforth rather than infinite rotation. It is also possible for certainstacks of holders 16 (e.g., two-holder stacks) to be fixed together at apredetermined phasing which being rotatably mounted to other holders 16or stacks of holders 16. The holders 16 nevertheless should have somedegree of rotatability with respect to each other such that they canmove to different phasings depending on the configuration of thealignment member 20.

Referring to FIG. 5 , each holder 16 can include an annular body 24comprising a first open end 26 for receiving a shaped charge therein,and a second opening 28. The annular body has a shape and configurationto receive and housing the shaped charge, as shown in FIG. 6 where anend of the shaped charge passes through the second opening 28 and canattach to the alignment connector 18. The annular body 24 can have a cupshape with a tapered inner surface, and can have projections 30 thatextend away from the cup shape to cooperate with corresponding recessesof the shaped charge 22. Various other configurations of the holder 16are possible for retaining the shaped charge, and can be designed basedon the particular shaped charge as well as other components of thesystem. For example, the holders may not have a tapered inner surface orother features should in the figures, depending on the charge that isused.

Turning back to FIG. 5 , in some implementations, the holder 16 alsoincludes a first coupling component 32 extending from a first side ofthe annular body 24, and a second coupling component 34 extending from asecond side of the annular body 24. The first and second couplingcomponents 32,34 of adjacent shaped charge holders 16 are rotatablyconnectable together to enable rotation of the adjacent shaped chargeholders 16 with respect to each other. The arrangement of the couplingcomponents 32,34 can be seen in FIGS. 1, 2, 3 and 4 . The first couplingcomponent 32 can be provided on a downhole side and the second couplingcomponent 34 can be provided on an uphole side for each of the shapedcharge holders 16. As shown in FIG. 2 , the top mounting unit 12 canhave a top attachment for rotatably coupling with the second couplingcomponent 34 of the top-most holder 16, and the attachment can have thesame configuration as that of the first coupling component 32.Similarly, the bottom mounting unit 12 can have a bottom attachment forrotatably coupling with the first coupling component 32 of thebottom-most holder 16, and the attachment can have the sameconfiguration as that of the second coupling component 34.

Referring back to FIGS. 5 and 6 , the first coupling component 32 can bea male component and the second coupling component 34 can be a femalecomponent. The male component can include a mushroom-shaped membercomprising a post 36 and a head 38. The post 36 can be mounted to a disk40 that is disposed on a side of an annular wall 42 of the body 24. Thepost 36 can be cylindrical, and the head 38 can be inwardly taperedextending away from the post and can have a flat end. Of course, variousstructures are possible for the male component to enable coupling withinthe female component of an adjacent holder 16 to facilitate retentiontherein and rotation therebetween.

Still referring to FIGS. 5 and 6 , the female component 34 can includeside walls 44 extending from the annular body and defining a chamber forreceiving the head 38 of the male component 32. The side walls 44 canhave notches 46 distributed around the periphery, which can facilitatebending of the outer part of the side walls 44 to facilitate insertionof the male component 32. Turning briefly to FIG. 3 , the femalecomponent 34 can include a lip 48 extending inwardly from an extremityof the side walls 44. The lip 48 can fit in the space adjacent the post36 and in between the head 38 and the disk 40 of the male component 32.The lip 48 fits over the head 38 and retains it within the chamber ofthe female component 34. The lip 48 and head 38 are part of an examplestructure that enables the female component to receive and retain themale component while enabling relative rotation along the longitudinalaxis. Other structures are also possible.

The connection between the holders 16 can enable axial retention, aswith the mechanism shown in FIGS. 5 and 6 for example, but theconnection could alternatively provide little to no axial retentionsince the tower of holders could be retained within the carrier andsandwiched between the top and bottom mounting units, such that externalstructures keep the holders together. In this case, the holders couldhave a male-female configuration, e.g., as shown in FIGS. 34A and 34B.In another example, the connection between shaped charge holders can bea clip instead of a male-female insertion, and the clip could bedesigned to make separation difficult. However, the holders could besecured together in this manner since they do not need to be decoupledbecause to phase or rephase one can simply attach different alignmentmember.

Turning now to FIG. 4 , the alignment member 20 can include a mountingsection 50 and an alignment section 52. The mounting section 50 issecurable with respect to the top mounting unit 12, while the alignmentsection 52 has a configuration that enables connection to the alignmentconnectors 18 of the holders 16 to provide the desired positioning andphasing. In the illustrated implementation, the alignment member 20 isin the form of an alignment rod, with both the mounting and alignmentsections being in rod form. However, it is noted that the alignmentmember could take forms other than a rod and could also include multipledistinct elements that are each secured to the mounting unit andconfigured to cooperate with certain holders. Nevertheless, theillustrated implementation shows an alignment rod 20 where the mountingsection 50 is a straight segment of the rod while the alignment section52 is a helical segment of the same rod.

The alignment section 52 can have a helical configuration, which can becircular, square, or another configuration. The helical form can beregular with a consistent diameter and pitch, or it could vary along thelength of the alignment section 52. The alignment section 52 has aconfiguration that, upon securing with respect to the mounting unit 50,provides connection points along the holding assembly that are securableto respective alignment connectors 18 to position the holders in apredetermined phasing. The alignment section 52 is shown as extendingaround and outside of the holders 16, but other arrangements could alsobe possible as long as the alignment connectors and holders are arrangedand configured accordingly. Being arranged on the outside of the holdingassembly can facilitate construction, assembly and minimizinginteraction with the holders themselves.

Thus, adjacent alignment connectors 18 of the shaped charge holders 16define an axial holder spacing (S) therebetween, and the helicalconfiguration of the adjustment section 52 has a pitch (P) that ispredetermined to position the connection points of the adjustmentsection 52 at the radial locations for attaching to the connectors 18that position the shaped charge holders 16. The axial holder spacing (S)can be smaller than the pitch (P), and the pitch (P) can be an integermultiple of the axial holder spacing (S). For instance, the P canequivalent to approximately 2S, 3S, 4S, 5S or 6S, to provide a phasingbetween adjacent shaped charge holders of 180°, 120°, 90°, 72° or 60°,respectively. Of course, other relationships between P and S arepossible for providing different phasings.

Still referring to FIG. 4 , the mounting section 50 of the alignment rod20 can be a straight bar that inserts into a corresponding slot 54 ofthe mounting unit 12. The slot 54 can have a circular cross-section andthe mounting section 50 can have a cylindrical shape, although they canhave other shapes and configurations for securing one to the other.Alternatively, the alignment member 20 could have another type of systemfor securing it to the mounting unit 12.

Turning now to FIG. 11 , the alignment member 20 can have certainproperties to provide desired structural characteristics. For example,when in the form of an alignment bar, it can have a length and diameterthat provide certain rigidity to retain the holders in a desired phasingwhile having a flexibility to facilitate some bending duringinstallation and winding around the holding assembly. The alignment bar20 can be composed of various materials, such as metal (e.g., steel),composite materials, or polymeric materials. The alignment member canalso have a solid structure, such as a solid metal bar, or could beconfigured as a tubular structure that is hollow depending on thematerials and method of manufacture. The alignment member can be made asa one piece integral structure, such as an elongated bar that has beenreformed from a straight bar to have a certain configuration (e.g.,straight segment and helical segment). Alternatively, the alignmentmember could be made from multiple components that are themselvesattached together. As noted above, there could be two or more alignmentbars that are provided for a single holding assembly, where thealignment bars are secured to the same mounting unit or to respectivetop and bottom mounting units.

In some implementations, the alignment bar has a diameter of about 1/16inch to about 3/16, or ⅛ inch. The alignment bar can have a length fromabout 10 inches to about 20 inches, and the bar can have a total lengthof about 12 inches to 28 inches, for example. The alignment bar can bemade of various materials, such as steel (e.g., carbon steel) or othercomparable metals, composites, or high strength materials.

In some implementations, the alignment bar could be configured to servean electrical purpose as well as the phasing alignment purpose. Forinstance, the alignment bar could be provided as a possible ground pathor through-communication path if sufficiently insulated. For example,the alignment bar could be configured as a tubular member with a borethrough which a through-wire can pass to extend along the entire lengthof the perforating gun to enable communication. The mounting units couldbe adapted appropriately to include structures and openings to enablepassage of the wire. When the rod is composed of metal, the conductivityof the rod could be leveraged, e.g., to provide redundant ground inaddition to the gun body. The alignment bar can of course be configuredin terms of size and shape depending on the functionalities of interestand the other components of the overall perforating gun. Thus, theinsulation, through-wire, bore, and so on, can be sized and provided forthe desired function. In addition, the alignment member could be coupledto the det cord (e.g., where the det cord is within a tubular alignmentmember which has apertures through which portions of the det cord canprotrude to contact the charges; or where the det cord is clipped orotherwise connected to the alignment member to follow a same trajectoryalong the holding assembly).

It is noted that the alignment member could have various structures andcross-sections. A bar with a solid cylindrical structure is illustratedin various figures, but the alignment member could have othercross-sectional configurations, such as an H, an I, a U, an L or a Tshaped cross-section. The alignment member could also have a plateshape, or a circular or square tubular shape. The alignment member couldhave the same cross-sectional shape along its entire length or it couldvary by including two or more, such as those described above. FIG. 33 isa schematic of a part of a plate shaped alignment member with integratedclips.

Referring now to FIGS. 1 to 4 , the alignment connector 18 is configuredand arranged to secure a point on the alignment member 20 with respectto the corresponding holder 16. In some implementations, the alignmentconnector 18 is configured such that it can be positioned at one axialposition along the holding assembly 8 but can be moved to any radialpoint around the longitudinal axis upon rotation of the correspondingholder 16. In this way, the alignment connector can be moved to anyradial point at which the alignment member 20 may intersect, dependingon the configuration of the alignment member 20.

The alignment connector 18 can take various forms and can be integratedinto the system in various ways. For example, in the illustratedimplementation as best shown in FIG. 6 , the alignment connector ismounted to a back end of the shaped charge 22 rather than to the holder16 itself. Thus, in this scenario, the alignment connector 18 is notdirectly connected to the holder 16 but it is able to secure the holderin place because the shaped charge 22 is secured to the holder 16.Alternatively, the alignment connector 18 could be directly connected tothe corresponding holder 16 as a separate piece or as an integral partof the holder 16.

Referring to FIGS. 6 and 7 , an implementation of the alignmentconnector 18 will be described in greater detail. The alignmentconnector 18 can be part of the same unit that is used as a detonatorcord clip and/or for securing a flexible line (e.g., a signal cord) thatis part of the perforating gun. For example, the alignment connector 18can include a main section 56 for coupling the shaped charge with adetonator cord, and an arm 58 extending from the main section 56 andcomprising a clip 60 securable to the alignment member 20. The alignmentconnector 18 can include a second arm 62 extending from the main section56 and comprising a second clip 64 securable to a signal cord.

The main section 56 of the alignment connector 18 can have variousstructures designed based on the type of shaped charge to be used. Inthe case of a universal shaped charged, for example, the illustratedmain section can be used where it has a base plate 66, opposed sidewalls 68, and an upper plate 70 defining a detonator cord passageway 72.The passageway also receives the notched end 74 of the shaped charge 22,as shown in FIG. 6 . The upper plate 70 has an opening 76 definedtherein for receiving the notched end 74 of the shaped charge 22 forconnection to the detonator cord.

Still referring to FIG. 7 , the arm 58 can be angled with respect to thebase plate 66. The arm 58 can include a first oblique section 78extending at an angle toward the shaped charge, the clip 60 beinglocated at an extremity of the first oblique section 78. The angle canbe between 30 and 60 degrees, for example. The first oblique section 78can be a U-shaped plate including two parallel strips that are joined byan end strip thereby defining an opening. The clip 60 can include ahook-shaped member that extends outwardly from the first oblique section78, and may define a rod-receiving region that faces away from theshaped charge and the holder. In addition, the clip 60 can be formed tobe flexible to enable insertion of the alignment member and then toexert a compression force to help secure it. The connector 18 and/or oneor more of its structures, can be formed from a single piece of sheetmetal. The arms can be formed such that they have some flexibility andresilience, thus facilitating manipulation when securing the clip 60 tothe alignment member.

In some implementations, the orientation of each clip-type alignmentconnector can be predetermined and it can be rotationally locked orsecured in place when connected to the charge when the detonation cordis secured in place. This can be due to the geometry of the rod, charge,and clip-type alignment connector, for example, such that all of thosecomponents find themselves positioned in the desired location forphasing alignment when the charges are rotated about the perforating gunaxis. In other implementations, when the alignment connectors 18′ arepart of or fixed to respective holders, as shown in FIG. 23 for example,the orientation and configuration of each alignment connector can alsobe predetermined and fixed. Alternatively, the alignment connectorscould be configured to have some movement (e.g., rotational, pivotal)with respect to the holder bodies or the charges.

As can be appreciated, the alignment connector 18 can be amultifunctional connector that serves as a detonation cord clip, asignal cord clip and an alignment member clip that holds these threecomponents of the perforating gun in place. The multifunctionalconnector can take various forms that are based on conventional or knowndetonation cord clips with the addition of an alignment member clipwhich can be in the form of an arm extending away from the main clipunit. A few example detonation cord clips are described in U.S. Pat.Nos. 4,762,067, 4,716,832, 4,542,695, 3,991,679, 9,598,941, for example.

The alignment member can couple to the charges in various ways. Forexample, as shown in FIG. 1 , the alignment member can take the form ofa rod or another elongated structure that is secured to clip-typealignment connectors attached to respective shaped charges.Alternatively, as shown in FIG. 23 , the alignment member can attach toalignment connectors that are part of the holders.

In another alternative configuration, the alignment member and thealignment connectors can be formed as a one-piece structure, that can bearranged so that the alignment connectors attach to the holders and/orcharges as the alignment member is configured to provide the phasing tothe charges. For instance, the alignment member could take the form of asheet that has a helical shape with clip geometry features arranged inspaced relation along its length to act as the alignment connectors. Inthis example, the predefined helix and connectors can be built into thesheet, and the alignment sheet can connect to all of the charges orholders. The alignment sheet could also be configured such that thebuilt-in alignment connectors could also function as detonation cordclips. This example could take the form of an elongated det cord clipwith a helical profile and multiple built-in det cord clip parts. Inthis regard, it should be noted that the alignment member could includeclip-type connectors along its length and the holders or charges couldinclude a cylindrical component around which the clip-like connectorscan fit to provide retention.

In another alternative configuration, the alignment member (e.g., rodshaped) could include notches to define locations in which the alignmentconnectors can sit. The alignment member (e.g., rod shaped) couldinclude an insulative sleeve that is configured to be clipped orotherwise attached to the alignment connectors. The sleeve could alsofacilitate electrical grounding path applications by excluding thecharge from the circuit.

The attachment of the alignment member (e.g., rod shaped) to the holderscould be done in various ways. For example, the alignment member couldattach to a rotational pivot joint on the side of the holder and whichwould clip onto the alignment member or slide onto the rod. Theattachment could also be provided such that the alignment connectorstake the form of a through-hole that passes through part of the side ofthe holder into which the alignment member could slide or clip. When thealignment member is a tube with a hollow center, the tubular alignmentmember could be provided with apertures and the alignment connectorscould include insertion elements that could be inserted inside theapertures for securing the components together. The alignment connectorcould of course be configured and shaped depending on the shape of thealignment member (e.g., rod, sheet, tube, or other).

In other alternative designs, the connection between the alignmentmember and the holders or shaped charge could take the form of amagnetic attachment mechanism or adhesive based attachment. A magneticattachment mechanism could include a pair of magnetically attractableelements provided on the holder or charge as well as the alignmentmember such that when aligned the magnetic elements hold together withsufficient force to retain the components in place. Adhesive basedmethods could include the use of an adhesive compound, such as glue,that can be manually applied to the appropriate locations of thealignment member and the holder or shaped charge during assembly. Insuch cases, the holders or charges could be provided with a mark thatindicates the desired location for applying the adhesive for securing tothe alignment member.

Regarding the arrangement of the holders, in some implementations eachholder of a shaped charge is rotatable with respect to adjacent holdersand, for the upper- and lower-most holders, with respect to the top andbottom mounting units respectively. However, in alternativeimplementations, the holders can have different arrangements androtatability with respect to certain components. For example, theassembly can include sets of holders with multiple holders in each set,where one or more of the sets can be made up of holders that are fixedwith respect to each other while the adjacent sets are rotatable withrespect to each other. This can facilitate providing multiple chargesper plane. In addition, in such configurations, the alignment member canbe configured to retain each set of charges at a desired phasinglocation and thus each set could include one or more alignmentconnector. In addition, the holders could be designed such that a singleholder component can receive multiple charges that have the same ordifferent orientation, and such multi-charge holders could be rotatablycoupled to each other as described above.

Regarding the holders, the design can be adapted based on variousfactors including the size and configuration of the shaped charge to beused, the manner in which the shaped charge is retained by the alignmentmember, and so on. FIGS. 5 and 24 to 27 show an example design of aholder 16 that male-female components 32, 34 for the rotationalcoupling, projections 30 that facilitate retention of the shaped charge,and the body has a certain configuration. The projections 30 can includetab section extending from the body and a distal catch confirmed to fitinto a groove or lip of the shaped charge. The projections 30 can alsoeach include wings that are integrated with or extend from either sideof the tab section. The projections 30 can be configured to be resilientsuch that they deflect outwardly upon insertion of the shaped charge,and then snap back to engage the shaped charge in place. In addition,the projections 30 can configured to allow free rotation of the chargewithin the cavity of the body, and/or to also allow the charges to beremoved, if desired, by bending back the projections and popping thecharge out.

In addition, the holders 16 can be composed of plastic materials and canbe made by molding processes. The holders can alternatively be made ofother materials, such as composites, and can be made using othermanufacturing methods. The holders 16 can be made based on a singledesign configuration so they are all identical and interchangeable. Therotatable coupling between the holders can also be provided for the topand bottom connectors, although the holders could be rotatably coupledtogether using one mechanism and then coupled to the top and bottomconnectors using other mechanisms.

FIG. 28 shows an alternative design where the projections 30 are thinnerand lack the wing members of the other design. FIG. 29 shows analternative design of the holder 16 where projections are not providedfor retaining the shaped charge, but rather includes a mounting ringwith a retention lip for retaining the shaped charge. The charge can beinserted into the cavity and the retention lip fits over and around partof the charge to retain it. The mounting ring can also provideadditional support for the male and female components 32, 34 to bealigned along the central axis of the perforating gun, since in thedesign of FIG. 28 and others the male and female components 32, 34partially hang over the rim of the body. FIG. 30 shows anotheralternative design where the holder 16 includes a slit through which aresilient retention wire or other structure can be inserted forretaining the charge in the cavity of the holder 16. It should beunderstood that various other structures could be used in holder designsfor retaining the charges and for enabling the rotational movement, asthe case may be.

Referring to FIG. 10 , the shaped charge holding system can be coupledto a tandem sub 4. The tandem sub 4 facilitates gun-to-gun connectionand further enhances the modularity of the overall system. For example,multiple shaped charge holding systems can be coupled together viacorresponding tandem subs 4, with each tandem sub 4 being located inbetween two adjacent holding systems. The tandem sub 4 is configured toprovide structural and electrical connection between the holdingsystems. The tandem sub 4 thus has a bottom end that can be coupled to atop end of a holding system, as shown in FIG. 1 ; and the tandem sub 4also has a top end that can be connected to the bottom end of an upholeholding system.

Turning to FIG. 8 , with continued reference to FIG. 10 , the topmounting unit 12 includes a detonator insertion bore 80 for receivingthe detonator from the tandem sub 4, as well as an annular strip 82 forelectrical connection with he tandem sub 4. Similarly, as shown in FIG.9 , the bottom mounting unit 14 has a configuration and connectionstructures for coupling with the holding assembly 8 on one side and adownhole tandem sub 4 on the other, as the case may be. FIG. 9 alsoshows a bottom attachment 84 that is configured to be rotatablyconnected to the male component of the bottom-most holder.

FIG. 13 shows the top mounting unit 12 coupled to the tandem sub 4, andFIGS. 14-16 show the internals of the top mounting unit which areprovided to receive certain components including the det cord and thealignment member, and part of the tandem sub. The det cord is insertedinto the top mounting unit and guided into overlapping contact with thedenotator. FIGS. 17 and 18 show the opposed sides of the top mountingunit 12.

Referring to FIG. 10 , in some implementations the tandem sub 4 caninclude a sub body 86 that defines a cavity 88 for receiving a printedcircuit board (PCB) assembly 90 as well as a bore 92 for receiving apressure bulkhead 94. The PCB assembly 90 has redundant groundingenabled by garter springs 96 that can fit into corresponding seats 98 inthe cavity 88. The PCB assembly 90 also has an addressable switch 100, adetonator 102, a signal input 104, and a signal output. In operation,the detonator 102 of the tandem sub 4 can be inserted into the boredefined in the top mounting unit for connection with the appropriatedetonation cord. Appropriate seals are also provided around the sub body86.

The garter springs 96 can be configured to provide a ground path,connect the detonator to the board, centralize the PCB within the cavity88, and secure the PCB in the cavity 88. FIG. 31 provides anillustration of the printed circuit board (PCB) assembly 90 mounted tothe top mounting unit 12. FIG. 22 provides an illustration showing thebottom mounting unit 14 interfacing with the tandem sub 4 which helps toalign the bottom mounting unit along the centerline.

With reference to FIGS. 35 to 45 , another implementation of theperforating gun 2 is shown. The perforating gun subassembly 6, whichincludes the shaped charge holding assembly 8, the top mounting unit 12and the bottom mounting unit 14, is coupled between a pair of tandemsubs 4 which can house respective PCB assemblies. In thisimplementation, the PCB assembly 90 includes a cartridge 110 having acartridge body 112 adapted to be connected to the sub body 86 within thecavity 88. The cartridge body 112 can be adapted to house electricalcomponents (e.g., the printed circuit board, among others) and thedetonator 102 configured to cooperate with the shaped charge holdingassembly to operate the perforating gun (e.g., to detonate the shapedcharges). The detonator receives the electrical signal from theelectronic components within the cartridge body 112, which is adapted torelay the electrical signal received from the bulkhead assembly 94.

It should be noted that the perforating gun 2 can be operated as atop-fired perforating gun, where the shaped charges are detonated insequence from top to bottom (e.g., from an upholemost shaped charge to adownholemost shaped charge). Alternatively, the perforating gun 2 can beoperated as a bottom-fired perforating gun where the shaped charges aredetonated in sequence from bottom to top. In some implementations, theperforating gun includes a plurality of shaped charge holding assemblieswhich can be respectively operable in a top-fire or a bottom-fireconfiguration. In other words, each shaped charge holding assembly canbe fired using the same operation sequence (e.g., top-fired orbottom-fired), or fired using varying operation sequences (e.g., a firstgun is top-fired and a second gun is bottom-fired). In thisimplementation, although the detonator 102 is positioned within thetandem sub 4 positioned uphole relative to the shaped charges, theperforating gun can still be operated in either one of the top- andbottom-fire configurations.

As seen in FIGS. 38 to 40 , the cartridge 110 can be provided with acoupling assembly 114 configured to engage the tandem sub 4 for securingthe cartridge body 112 within the cavity 88. It is appreciated thatsecuring the cartridge 110 within the cavity positions the electricalcomponents of the PCB assembly in a predetermined position relative tothe perforating gun subassembly and/or relative to the bulkheadassembly. In this implementation, the coupling assembly 114 includes oneor more protrusions 116 shaped and sized to engage the inner surface ofthe sub body 86. The inner surface of the sub body 86 can include one ormore recesses 118 for receiving respective protrusions 116 and holdingthe cartridge 110 within the cavity. In some implementations, the recess118 extends circumferentially around the surface of the cavity 88 suchthat the protrusions 116 can engage the recess at any point therealong(e.g., 360 degrees around the inner surface of the cavity).

The coupling assembly 114 can further include a resilient element 120adapted to bias the protrusions 116 outwardly to facilitate engagementwith the recess 118. In this implementation, the resilient element 120can include a resilient arm 122 extending outwardly from the cartridgebody 112 and having a free distal end, where the protrusion 116 ispositioned proximate the free distal end 74. It is noted that theresilient arm 122 is adapted to exert an outward radial force to biasthe protrusion outwardly and within the recess. It should therefore beunderstood that the resilient arm 122 is adapted to pivot (e.g., aboutits base) to enable its free end to move radially relative to the innersurface of the cavity 88. It is thus appreciated that the cartridge 110can be connected to the tandem sub 4 by sliding the cartridge body 112within the cavity 88 until the protrusions 116 engage the recess 118. Asseen in FIGS. 38 to 40 , the coupling assembly 114 can include tworesilient arms 122, and therefore two protrusions 116 adapted to engagethe recess on opposite sides of the cartridge. However, it isappreciated that other configurations are possible, such as havingadditional resilient arms and/or protrusions, either aligned with oneanother to engage the same recess, or offset axially along the cartridgebody to engage additional recesses defined within the cavity, forexample.

As mentioned, the PCB assembly 90 is adapted to be operatively connectedto the bulkhead assembly, and can be adapted to be electricallyconnected to the pressure bulkhead 94. As seen in FIG. 40 , thecartridge body 112 includes a connection bore 115 defining a PCBassembly input adapted to receive a connection pin of the pressurebulkhead therein when positioning the cartridge 110 within the cavity.The connection bore 115 and the pressure bulkhead 94 are slidablyconnected together, where the connection pin slides into the connectionbore 115 when the cartridge 110 is positioned within the cavity 88(e.g., similar to an RCA-type connection). As such, it is appreciatedthat the contact surface between the connection bore 115 and theconnection pin can correspond to the lateral surface of the connectionpin along which the sliding connection is defined. In other words, thesliding connection is defined by a radial connection of the pressurebulkhead (e.g., of the connection pin) within the connection bore 115,instead of an end-to-end connection

It is noted that, by coupling the cartridge body 112 within the cavityvia the engagement of the recess with the protrusions, combined with thegenerally static pressure bulkhead 94 secured within the bore 92 definesand generally robust connection between the connection pin and theconnection bore 115 (i.e., the configuration of the tandem sub andcartridge is adapted to prevent disconnection between the componentshoused therein). The cartridge can thus be in a predetermined position(e.g., when the protrusions engage the recess) and the position of thebulkhead assembly is in a similarly predetermined position (e.g., whensecured in the bore) such that the position of the connection pinrelative to the connection bore 115 can be guaranteed along the slidingconnection.

In this implementation, the recess 118 is larger than the protrusions116 to enable movement of the cartridge 110 within the cavity 88 (e.g.,axially along the cavity). As seen in FIG. 39 , the cartridge body 112defines a play 125 (e.g., a void or generally empty space enablingmovement therein) with the axial surface of the cavity 88, which cansubstantially correspond to the amount of play between the protrusionand the uphole portion of the larger recess. The size of the protrusions116, the recess 118 and the play 125 are adapted to enable movement ofthe cartridge during operation of the perforating gun, e.g., duringdetonation of the shaped charges. As such, the electronic components areat least partially protected from shocks, such as shocks created fromoperating the perforating gun and/or other energetically orhydraulically actuated tools. It should be noted that, during movementof the cartridge body, the connection bore 115 is adapted to slide alongthe connection pin of the pressure bulkhead, thereby keeping theelectrical connection established between the bulkhead assembly and thePCB assembly.

In this implementation, the PCB assembly can be provided with aresilient component, such as a spring, adapted to bias the cartridge ina predetermined position, absorb at least some of the shock (e.g., fromthe detonation) and/or revert the cartridge body 112 back into thepredetermined position following movement thereof within the cavity. Asseen in FIGS. 38 to 40 , the PCB assembly 90 can include a biasingelement 130, such as a spring 132, coupled to the cartridge andextending between the cartridge and an axial surface of the cavity. Thespring 132 can be adapted to protect the cartridge by absorbing at leastsome of the forces (e.g., from the detonation) and revert the cartridgebody 112 back in its initial position (e.g., abutting against the topmounting unit) following movement thereof within the cavity. It shouldthus be noted that the electrical connection system and the tandem subfacilitate connection (both structural and electrical) between thevarious components of the perforating gun.

Now referring to FIGS. 41 to 43 , the PCB assembly 90 further includes agrounding system 140 defining one or more ground paths for the variouselectrical connections of the electrical connection system. It should beunderstood that the grounding system 140 is configured to ensureelectrical communication to and through the PCB assembly, e.g., ensureelectrical connection with the switch and the detonator. In thisimplementation, the grounding system 100 is adapted to define aplurality of independent ground paths between the PCB assembly 90 andthe tandem sub. The grounding system 140 can include one or moregrounding pins 142 coupled to the PCB assembly 90 and extendingtherefrom to engage a grounding surface, such as the tandem sub, forexample. It is appreciated that the tandem sub can be at least partiallymade of a metallic material in order to define the grounding surface forthe grounding pins 142.

The grounding pins 142 can be independent from one another, and therebydefine independent grounding paths. As such, if one grounding pin 142malfunctions (e.g., breaks and/or is no longer adapted to contact thetandem sub), then another one of the grounding pins 142 can stillprovide the required grounding path. In some implementations, thegrounding pins 142 include pogo pins having a spring-loaded retractablehead which can facilitate engagement of the cartridge within the cavity88, and engagement of the pins with the grounding surface.

In this implementation, the grounding system 140 includes a secondarygrounding component 144 defining a secondary grounding path (i.e., thegrounding pins 142 respectively defining primary grounding paths). Morespecifically, the spring 132 extending between the cartridge body 112and the tandem sub 4 can be made of a metallic material, and cantherefor be adapted to conduct electricity therebetween. The secondarygrounding path is independent from the grounding paths defined by thegrounding pins 142, and can thus serve as increased security to have agrounding path between the PCB assembly and the tandem sub. It istherefore noted that the PCB assembly includes components adapted toprotect the electric components. For instance, the cylindrical plastichousing and the grounding system 140 protect the electrical componentsfrom mechanical- and electrical-based complications, such as the forcescreated from detonating the detonation cord, by providing a bearingsurface to take the brunt of the shock (e.g., the spring 132), and byproviding grounding paths to protect the electrical components.

Now referring to FIGS. 39, 44 and 45 , the detonator 102 can beremovably coupled within the cartridge body 112 and in electricalcommunication with the addressable switch 100. In some implementations,the cartridge body 112 includes a support member 150 shaped and adaptedfor receiving the detonator 102 and positioning the detonator in apredetermined position within the cartridge body 112. As seen in FIG. 45, the tandem sub 4, and the cartridge 110 held within, are adapted to bepositioned adjacent the top mounting unit 12 of the shaped chargeholding assembly. In addition, the top mounting unit 12 includes adetonator insertion bore 80 configured to receive a portion of thedetonator 102, which extends further than the cartridge body 112 (asseen in FIGS. 38, 39, 44 and 45 ). More particularly, the detonator 102has a proximal end adapted to abut a portion of the support member 150within the cartridge body 112, and a distal end extending outwardly fromthe cartridge body 112. The distal end can thus be adapted to engage thedetonator insertion bore 80 prior to the cartridge body contacting themounting unit.

In this implementation, the support member 150 includes support arms 152having a U-shaped supporting surface for holding the detonator 102. Insome implementations, the detonator 102 can clip into the support arms152 to secure its position therein, although other configurations arepossible. As seen in FIGS. 44 and 45 , the proximal portion of thedetonator 102 is held in the support member 150, with the distal portionextending outwardly to engage the mounting unit and the detonation cord.The support member 150 can further include a rear support 154 adapted toblock axial movement of the detonator 102 in one direction (e.g., towardthe inside of the cartridge). More specifically, the proximal endsurface of the detonator 102 is adapted to abut against the rear support154, which blocks movement thereof and thereby positions the detonatorin a predetermined position within the cartridge body 112. Is it thusnoted that the length of the distal portion of the detonator 102extending into the detonator insertion bore 80 of the mounting unit 12can be determined when the cartridge is in position (e.g., relative tothe tandem sub and/or the mounting unit). It should be noted that someof the implementations described above are described further inApplicant's co-pending application No. 63/260,892, which is herebyincorporated by reference in its entirety.

In terms of assembly and deployment of the perforating gun, the tandemsub 4 and the holding system 6 can be pre-assembled off-site and shippedtogether to the well site as a unit, if desired. Alternatively, the unitcould be pre-assembled at a manufacturing site except for the alignmentbar such that an alignment bar having the desired configuration toprovide a particular phasing for each perforating gun can be installedbefore shipping, based on well design criteria. In some implementations,the bottom mounting unit can be removed and the alignment rod can beplaced over the tower of holders until the mounting section connectsinto the top mounting unit and the alignment connectors are clipped ontothe alignment bar; then the bottom mounting unit is reinstalled onto thebottom-most holder; and then the carrier is installed over theperforating gun subassembly. The detonation cord and signal cord can berun in the same helical manner and direction as the alignment rod, forexample. It is also noted that inventory of the various components canbe kept such that perforating guns can be assembled efficiently whereonly the selection of the alignment member is required for providing acertain desired phasing for the charges. Thus, a set of differentalignment members can be kept in inventory while the remainder of thecomponents are standard and used for all phasing implementations.

While the alignment concept has been described herein in connection withaligning shaped charges for a perforation gun, it is noted that theconcept could also be used in other tools and operations in oil and gasapplications, geology applications requiring downhole tools, or otherapplications that require phasing of certain components. For example,the alignment bar could be used to align any components that arerotatably coupled along a longitudinal axis of a tubular wellbore tool,or other device, in order to align the components at a desired phasing.Such components could be shaped charge holders, as described in detailherein, and could also be components such as valves, sensors, inflow oroutflow devices, tubular sections, and so on.

The alignment strategy described herein can facilitate freedom ofmanufacturing, for example since a single design of the holding assemblyand mounting units can be manufactured to cooperate with multipledifferent alignment member designs to provide the phasing of interestfor a given perforation gun. Each perforation gun can be provided withits own desired phasing by simply using a corresponding alignmentmember, while the rest of the components of the perforating gun remainthe same. The alignment member can be a relatively simple component,such as a single-piece rod that has been formed to provide an alignmentconfiguration when secured to the alignment connectors along the holdingassembly. Indexing the charge orientation to the carrier can involve thecharge orientation being couple to the top mounting unit which isrotationally secured to the carrier via a system, such as agroove-and-key system. However, it is also possible to not indexrelative to the carrier since each holder assembly itself is providedwith the desired charge phasing via the alignment member. When multipleguns are to be phased or indexed relative to each other, then indexingto the carrier can be an effective method to do so, but in cases wheregun-to-gun orientation is not important then the system may or may notbe indexed to the carrier. In other words, the system can be configuredsuch that if the alignment tab is removed, the charges and top mountingunit would remain connected in the desired phasing but they could beallowed to freely rotate within the gun carrier.

Referring to FIGS. 1 and 3 , the carrier 10 can have a scalloped shapethat includes thinner scallop sections around the entire circumferenceat each shaped charge location, such that the shaped charges do not needto be oriented with respect to the carrier. No matter where each shapedcharge is oriented after connection to the alignment member, the chargewill face part of a scallop section to facilitate operation of thecharges when detonated. The use of a scalloped carrier also enablesinventory enhancements as a single carrier design can be used for anyphasing arrangement. In addition, if the alignment member provides someplay or small error in the phasing, the scalloped design of the carriermaintains good performance.

Referring to FIGS. 32A to 32G, it is noted that various configurationsare possible for phasing the charges using the alignment member. Thesefigures schematically show six holders in between top and bottommounting units, with an alignment system coupled to the holders. FIG.32A shows a 180 degree phasing, FIG. 32B shows 0 degree phasing, FIG.32C shows a hybrid 0 and 180 degree phasing where adjacent pairs ofcharges are oriented together, and FIG. 32D shows 90 degree phasing.FIG. 32E shows an alternative arrangement where two alignment membersare used to provide 180 degree phasing. It is noted that two or moredistinct alignment members could be provided, each being inserted into acorresponding location in the top mounting unit, and configured suchthat the set of alignment members provide a desired phasing while notbeing located in front of the charges. For multiple alignment members,the top mounting block could be provided with appropriate number ofopenings, and the alignment members could be the same or different fromeach other and could be straight or helical or have anotherconfiguration. FIG. 32F shows an arrangement where adjacent pairs ofholders are connected together and the alignment member is connected toeach pair by a single alignment connector. FIG. 32G shows a branchedalignment member that provides 180 degree phasing. It should beunderstood that numerous variants of these arrangements can beimplemented to provide the desired phasing of the shaped charges.

In some implementations, the alignment member is manufactured in thepredetermined configuration to provide a certain phasing once installed.Thus, a straight steel bar can be subjected to a bending process to makethe helical section of the alignment bar, which can then be installed inthe perforating gun to provide the desired phasing. Alternatively, thealignment member could be given the desired helical configuration “insitu”, e.g., but mounting a straight bar to the top and bottom mountingunits and then using relative rotation between the two opposed unit tocause the bar to twist into the desired helical configuration. Themounting units could be provided with a clocking system to provide thedesired degree of rotation. Appropriate metalwork equipment andprocessing could be used in conjunction with this method of makinghelical alignment bars.

1.-94. (canceled)
 95. A perforating gun for deployment in a wellboreextending within an underground reservoir, comprising: a shaped chargeholding assembly, comprising: shaped charge holders that are arranged ina side-to-side configuration and wherein at least some adjacent pairs ofthe shaped charge holders are infinitely rotatable with respect to eachother in a rotation state; a mounting unit coupled to the holdingassembly; and an alignment system comprising: alignment connectorssecurable with respect to respective shaped charge holders or shapedcharges; an alignment member comprising: a mounting section configuredto be mounted with respect to the mounting unit to secure the alignmentmember with respect thereto; and an elongated alignment sectionextending from the mounting section along the holding assembly andconfigured to secure the shaped charges via the alignment connectors toorient the shaped charges in a predetermined phasing in an alignedstate.
 96. The perforating gun of claim 95, wherein the alignment membercomprises an alignment rod.
 97. The perforating gun of claim 95, whereinthe alignment member is composed of metal and provides electricalconduction.
 98. The perforating gun of claim 95, wherein the shapedcharge holders are independently rotatable with respect to each other.99. The perforating gun of claim 95, wherein the alignment system has asingle alignment member for phasing the shaped charges.
 100. A shapedcharge holder, comprising: an annular body comprising a first open endfor receiving a shaped charge therein, and a second opening throughwhich an end of the shaped charge can pass for connection with adetonation cord; a first coupling component extending from a first sideof the annular body; and a second coupling component extending from asecond side of the annular body, wherein the first coupling componentand the second coupling component are configured such that adjacentshaped charge holders are rotatably connectable together by engagementof the first and second coupling components to provide infinite rotationwith respect to each other about a longitudinal axis.
 101. The shapedcharge holder of claim 100, wherein the first and second couplingcomponents are configured to axially retain adjacent holders together toresist or prevent decoupling.
 102. The shaped charge holder of claim100, wherein the first and second coupling components provide amale-female connection.
 103. The shaped charge holder of claim 102,wherein the male component is rigid, and the female component comprisesresilient arms to receive and snap onto the male component.
 104. Theshaped charge holder of claim 102, wherein the female componentcomprises a cavity defined by rigid walls and the male componentcomprise resilient arms insert and snap into the female component. 105.A perforating gun for deployment in a wellbore extending within anunderground reservoir, comprising: shaped charge holders coupled in aside-to-side configuration and wherein adjacent pairs of the shapedcharge holders are infinitely rotatable with respect to each other, theshaped charge holders being configured to receive and support respectiveshaped charges; an alignment system configured to orientate the coupledshaped charge holders in a predetermined phasing configuration.
 106. Theperforating gun of claim 105, wherein the alignment system is configuredto secure the shaped charge holders to prevent rotation thereof oncepositioned in the predetermined phasing configuration.
 107. Theperforating gun of claim 105, further comprising a top mounting unitrotatably coupled to a top-most shaped charge holder.
 108. Theperforating gun of claim 105, further comprising a carrier in which thetop mounting unit, the shaped charge holders and the alignment systemare located.
 109. The perforating gun of claim 105, wherein the shapedcharge holders are rotatably mounted directly to each other.
 110. Theperforating gun of claim 105, further comprising a bottom mounting unitrotatably coupled to a bottom-most shaped charge holder.
 111. Theperforating gun of claim 105, wherein the shaped charge holders areinfinitely rotatable with respect to each other prior to being held inplace by the alignment system.
 112. A method for manufacturing aperforating gun, comprising: mounting a series of shaped charge holderstogether so as to be rotatable with respect to each other; mountingshaped charges within the holders; aligning the shaped charges in apredetermined phasing, comprising: rotating the holders to respectivepositions; and securing the adjacent shaped charges so as to benonrotatable to produce a phased shaped charge assembly; and installingthe phased shaped charge assembly in a carrier.